Re: Mike Marcum Ferrite Cores

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>

Well, if you buy 'em you probably won't want to grind em up lol. 
They're good for up to 1 MHz, tho their max sweet spot is 500 kHz. So 
they'll probably work for what you have in mind. The down side is 
that they have a $600 minimum order and 10-week lead time at the time 
I ordered them late last year. They're more of a manufacturer than a 
distributer/vendor (couldn't find one for them since they sell mostly 
to other manufacturers). IRRC I ordered 100 pcs to reach the minimum, 
but since sold the extras I had on ebay. I might do that again at 
some point if I ever get the time and need more cores. I could do a 
bulk buy similar to the cd942c20p15k caps, but probably wouldn't be 
enough interest to reach the minimum. You might give them a call and 
if you're lucky they might save you some work and just sell you the 
ferrite powder before they kiln it (unless they're like nst makers 
that refuse to sell unpotted nst's), but I'd guess the $600 minimum 
would still apply.

Mike


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, October 11, 2005 1:35 PM
Subject: Re: Mike Marcum Ferrite Cores


> Original poster: mecortner@xxxxxxxxxx
> >Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>
>
> >You can buy a pole xmfr for the price of a large ferrite core. We
> >sell 10 kVA, 14.4 kV/220 volt units for only $95!!
>
>
> Actually D.C. I thought about that when I wound the thing
> but as luck would have it I live quite a distance from
> you. I'm in California, way up north near Mt Shasta and
> shipping would be prohibitive no doubt. Actually I'm
> seriously looking at what Terry's up to right now. You
> know, when all this solid state stuff first started I
> just thought it was a joke, a new/fun way to blow up
> transistors, but the results are looking real now!
> The newest design looks so simple that I might even
> give it a whirl? Still for the life of Me I can't
> figure out what that little 5uF poly cap is doing in
> parallel with the C-drive caps's?
>
> ---- Matt Cortner ----
>
>
> >Original poster: "Mike" <mike.marcum@xxxxxxxxxxxx>
> >C-cores. Each one is 2.25" x 4" with a 1" square cross-section. 8 of
> >these are being put together in a modified E with the 2x2" center the
> >primary and the 4 secondaries on each side (can be paralleled or
> >series'd externally to get 12.5-50kV with 370vdc in). I did it this
> >way to minimise wire length for a given # of turns (litz is
> >expensive) and have core gaps for built in current limiting. It's the
> >P ferrite from Magnetics (
> >http://www.mag-inc.com/ferrites/ferrite_e_i_u_cores.asp ). Part # is
> >OP49925UC. Biggest non-custom core they have.
>
>
> That is a pretty huge core size for sure! I know
> from previous posts that your somewhat familiar
> with esoteric technology so you might have an idea
> what I'm up to. I'm also building an inverter, not
> the solid state kind though, a rotary type with rare
> earth magnets. I plan on driving a coil with it. What
> I need to do is cast a special stator core configuration.
> I plan on grinding up some ferrite cores on a wet wheel,
> separating out the magnetic dust and mix w/ epoxy for
> casting material. And I was curious as to what you
> thought the suitability of the cores you have are to this
> purpose? Also about what price did you pay per piece?
> Thanks.
>
> ---- Matt Cortner ----